MicroK8s : Dynamic Volume Provisioning (NFS)2024/06/14 |
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To use Dynamic Volume Provisioning feature when using Persistent Storage, it's possible to create PV (Persistent Volume) dynamically without creating PV manually by Cluster Administrator when created PVC (Persistent Volume Claim) by users. |
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| [1] |
Configure NFS Server on any node, refer to here.
On ths example, it uses [/home/nfsshare] directory on NFS Server that is running on [nfs.srv.world (10.0.0.35)]. |
| [2] | Install NFS Client Provisioner with Helm. |
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root@dlp:~#
microk8s helm3 repo add nfs-subdir-external-provisioner https://kubernetes-sigs.github.io/nfs-subdir-external-provisioner/
# nfs.server = (NFS server's hostname or IP address) # nfs.path = (NFS share Path) root@dlp:~# microk8s helm3 install nfs-client -n kube-system --set nfs.server=10.0.0.35 --set nfs.path=/home/nfsshare nfs-subdir-external-provisioner/nfs-subdir-external-provisioner
NAME: nfs-client LAST DEPLOYED: Fri Jun 14 03:48:46 2024 NAMESPACE: kube-system STATUS: deployed REVISION: 1 TEST SUITE: Noneroot@dlp:~# microk8s kubectl get pods -n kube-system NAME READY STATUS RESTARTS AGE ..... ..... nfs-client-nfs-subdir-external-provisioner-864f5ff99b-rfqkz 1/1 Running 0 8m52s |
| [3] | This is an example to use dynamic volume provisioning by a Pod. |
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root@dlp:~# microk8s kubectl get storageclass NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE microk8s-hostpath (default) microk8s.io/hostpath Delete WaitForFirstConsumer false 107m nfs-client cluster.local/nfs-client-nfs-subdir-external-provisioner Delete Immediate true 9m29s
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: my-provisioner
spec:
accessModes:
- ReadWriteOnce
# specify StorageClass name
storageClassName: nfs-client
resources:
requests:
# volume size
storage: 5Gi
root@dlp:~#
root@dlp:~# microk8s kubectl apply -f my-pvc.yml persistentvolumeclaim/my-provisioner configured microk8s kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE my-provisioner Bound pvc-74a17dbd-6743-4472-9519-4f0b765fa2b4 5Gi RWO nfs-client <unset> 3m32s # PV is generated dynamically root@dlp:~# microk8s kubectl get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE pvc-74a17dbd-6743-4472-9519-4f0b765fa2b4 5Gi RWO Delete Bound default/my-provisioner nfs-client <unset> 4m9s pvc-fbf13c3e-0c3d-4ab0-bd26-0f139fdf1643 30Gi RWX Delete Bound container-registry/registry-claim microk8s-hostpath <unset> 112m
root@dlp:~#
vi my-pod.yml
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
selector:
matchLabels:
run: my-nginx
replicas: 1
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: nginx
ports:
- containerPort: 80
volumeMounts:
- mountPath: /usr/share/nginx/html
name: nginx-pvc
volumes:
- name: nginx-pvc
persistentVolumeClaim:
# PVC name you created
claimName: my-provisioner
microk8s kubectl apply -f my-pod.yml deployment.apps/my-nginx created root@dlp:~# microk8s kubectl get pods -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-nginx-66fc75ffb8-lkbzz 1/1 Running 0 2m45s 10.1.142.88 dlp.srv.world <none> <none>root@dlp:~# microk8s kubectl exec my-nginx-66fc75ffb8-lkbzz -- df /usr/share/nginx/html Filesystem 1K-blocks Used Available Use% Mounted on 10.0.0.35:/home/nfsshare/default-my-provisioner-pvc-74a17dbd-6743-4472-9519-4f0b765fa2b4 164028416 0 155623424 0% /usr/share/nginx/html # verify accessing to create test index file root@dlp:~# echo "Nginx Index" > index.html root@dlp:~# microk8s kubectl cp index.html my-nginx-66fc75ffb8-lkbzz:/usr/share/nginx/html/index.html root@dlp:~# curl 10.1.142.88 Nginx Index # when removing, to remove PVC, then PV is also removed dynamically root@dlp:~# microk8s kubectl delete deployment my-nginx deployment.apps "my-nginx" deleted root@dlp:~# microk8s kubectl delete pvc my-provisioner persistentvolumeclaim "my-provisioner" deleted root@dlp:~# microk8s kubectl get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE pvc-fbf13c3e-0c3d-4ab0-bd26-0f139fdf1643 30Gi RWX Delete Bound container-registry/registry-claim microk8s-hostpath <unset> 120m |
| [4] | To use StatefulSet, it's possible to specify [volumeClaimTemplates]. |
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root@dlp:~# microk8s kubectl get storageclass NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE microk8s-hostpath (default) microk8s.io/hostpath Delete WaitForFirstConsumer false 122m nfs-client cluster.local/nfs-client-nfs-subdir-external-provisioner Delete Immediate true 24m
root@dlp:~#
vi statefulset.yml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: my-mginx
spec:
serviceName: my-mginx
replicas: 1
selector:
matchLabels:
app: my-mginx
template:
metadata:
labels:
app: my-mginx
spec:
containers:
- name: my-mginx
image: nginx
volumeMounts:
- name: data
mountPath: /usr/share/nginx/html
volumeClaimTemplates:
- metadata:
name: data
spec:
# specify StorageClass name
storageClassName: nfs-client
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 5Gi
microk8s kubectl apply -f statefulset.yml statefulset.apps/my-mginx created root@dlp:~# microk8s kubectl get statefulset NAME READY AGE my-mginx 1/1 10sroot@dlp:~# microk8s kubectl get pods -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES my-mginx-0 1/1 Running 0 15s 10.1.142.89 dlp.srv.world <none> <none>root@dlp:~# microk8s kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE data-my-mginx-0 Bound pvc-ea072275-904a-4529-9fd1-453b4c5ff007 5Gi RWO nfs-client <unset> 46sroot@dlp:~# microk8s kubectl get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE pvc-ea072275-904a-4529-9fd1-453b4c5ff007 5Gi RWO Delete Bound default/data-my-mginx-0 nfs-client <unset> 72s pvc-fbf13c3e-0c3d-4ab0-bd26-0f139fdf1643 30Gi RWX Delete Bound container-registry/registry-claim microk8s-hostpath <unset> 124m |
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